Q. No.A point object \(O\) is placed at a distance \(20\) cm from a biconvex lens of the radius of curvature \(20\) cm and \(\mu=1.5.\) The final image produced by lens and mirror combination will be at:
1.
\(10\) cm from the mirror
2.
\(20\) cm from the lens
3.
\(-20\) cm from the lens
4.
\(-15\) cm from the mirror
A concave lens forms the image of an object such that the distance between the object and image is \(10\) cm. If magnification of the image is \(\frac{1}{4},\) the focal length of the lens is:
1. \(-\frac{20}{3}~\text{cm}\)
2. \(\frac{20}{3}~\text{cm}\)
3. \(\frac{40}{9}~\text{cm}\)
4. \(-\frac{40}{9}~\text{cm}\)
Which one of the following is correct regarding the scattering of light?
| 1. | The light of shorter wavelengths is scattered much more than that of large wavelengths if the size of the scatterer \(a>>\lambda\). |
| 2. | The light of longer wavelengths is scattered much more than that of shorter wavelengths if the size of the scatterer \(a>>\lambda\) . |
| 3. | All wavelengths are scattered unequally if the size of the scatterer \(a<<\lambda\) . |
| 4. | All wavelengths are scattered equally if the size of the scatterer \(a>>\lambda\) . |
Assertion: The number of images of an object held between two plane mirrors perpendicular to each other is 3.
Reason: Number of images = , where is the angle between the mirror in degree.
(1) Both Assertion and Reason are true and the reason is the correct explanation of the assertion.
(2) Both Assertion and Reason are true but the reason is not the correct explanation of the assertion.
(3) Assertion is a true statement but Reason is false.
(4) Both Assertion and Reason are false statements.
The size of the image formed by a convex lens is one-fourth os the size of a real object. If the focal length of the lens is 30 cm, then the distance of the object from the lens is
1. 150 cm
2. 120 cm
3. 90 cm
4. 60 cm
Assertion: When a convex glass lens is dipped in water, its focal length increases.
Reason: When the lens is dipped in water, its light-bending capacity increases.
(1) Both Assertion and Reason are true and the reason is the correct explanation of the assertion.
(2) Both Assertion and Reason are true but the reason is not the correct explanation of the assertion.
(3) Assertion is a true statement but Reason is false.
(4) Both Assertion and Reason are false statements.
Minimum angular magnification produced by an astronomical telescope having a focal length of field lens and ocular 200 cm and 5 cm respectively is
1. 10
2. 20
3. 30
4. 40
Assertion: A convex mirror is used as a rearview mirror.
Reason: Convex mirror always forms a virtual, erect, and diminished image for real objects.
(1) Both Assertion and Reason are true and the reason is the correct explanation of the assertion.
(2) Both Assertion and Reason are true but the reason is not the correct explanation of the assertion.
(3) Assertion is a true statement but Reason is false.
(4) Both Assertion and Reason are false statements.
Assertion: The air bubble shines in water.
Reason: Air bubble in water shines due to the refraction of light.
(1) Both Assertion and Reason are true and the reason is the correct explanation of the assertion.
(2) Both Assertion and Reason are true but the reason is not the correct explanation of the assertion.
(3) Assertion is a true statement but Reason is false.
(4) Both Assertion and Reason are false statements.
A man runs towards a stationary plane mirror with a velocity 15 m/s. The magnitude of the velocity of the man relative to his image is
1. 15 m/s
2. 30 m/s
3. 45 m/s
4. Zero
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